In December 2016, the U.S. Food and Drug Administration (FDA) granted Rubraca accelerated approval in ovarian cancer patients whose tumors have a BRCA mutation, and whose disease had advanced despite two or more rounds of chemotherapy. Because of the results of this new trial, the company plans to submit a supplemental New Drug Application (sNDA) for a second-line and later maintenance treatment indication for all women with platinum-sensitive ovarian cancer who responded to their most recent platinum treatment.

In the trial, the drug hit the primary endpoint of improved progression-free survival (PFS) in each of the three populations studied. PFS was improved in the Rubraca group compared to placebo, a key secondary endpoint.

“We are very pleased with these positive ARIEL3 topline results that strongly demonstrate the potential of rucaparib to help women with platinum-sensitive, advanced ovarian cancer,” said Patrick Mahaffy, president and chief executive officer of Clovis, in a statement. “These results reinforce the potentially foundational role of rucaparib in the management of advanced ovarian cancer, as demonstrated by both investigator review and the blinded independent central review. Most importantly, we are grateful to the patients, caregivers and investigators who participated in this study. We look forward to sharing these data in greater detail at a medical meeting later this year and submitting our sNDA as rapidly as possible, with the ultimate goal of making rucaparib available to more women battling ovarian cancer.”

The ARIEL3 study was a double-blind, placebo-controlled, Phase III trial that investigated 564 women with platinum-sensitive, high-grade ovarian, fallopian tube, or primary peritoneal cancer. It looked at three defined molecular sub-groups. They were tumor BRCA mutant (tBRCAmut) patients, inclusive of germline and somatic mutations of BRCA; HRD-positive patients, including BRCA-mutant patients and BRCA wild-type with high loss of heterozygosity, or LOH-high patients; and third, the intent-to-treat population, or all patients treated in ARIEL3.

Rubraca was the first ADP-ribose polymerase (PARP) inhibitor to be approved by the FDA as a monotherapy for patients with deleterious BRCA mutation.

Clovis stock soared at the news. Shares traded on June 16 for $59.90, and are currently at $88.83.

On March 27, the FDA approved Tesaro’s own PARPi, Zejula (niraparib) for maintenance treatment of women with recurrent epithelial ovarian, fallopian tube, and primary peritoneal cancer who are in a complete or partial response to platinum-based chemotherapy. It was the first PARPi that doesn’t require BRCA mutation or other biomarker testing.

AstraZeneca (AZN) also has a PARPi, Lynparza, which will likely feel some pressure from Rubraca, if it gets approved for extended indications. And Pfizer (PFE) acquired Medivation (MDVN) and its PARPi for $14 billion.

Michael Schmidt, an analyst with Leerink,wrote, “The results look particularly impressive when compared to previous competitor data and we think should support a broad label for Rubraca in a broad 2L maintenance patient population, independent of BRCA/HRD status and testing. We recently initiated coverage of Clovis with an OP (outperform) rating. The top-line data reported this morning clearly reflect the best-case outcome for CLVS highlighted in our prior report indicating that efficacy of the three leading PARP inhibitors looks very comparable and we expect shares to trade up significantly. With best-case data in hand, we think Clovis should be a prime takeout candidate, and we reiterate our OP rating on the stock.”